Dynamic sampler fun

main.go

package main

import (
	"fmt"
	"math/rand"
	"time"

	dynsampler "github.com/honeycombio/dynsampler-go"
)

type samplerConfig struct {
	Rate       uint
	WindowSize int
}

type testSampler struct {
	sampler dynsampler.Sampler
}

func (t *testSampler) init(config samplerConfig) error {
	t.sampler = &dynsampler.AvgSampleWithMin{
		GoalSampleRate:    int(config.Rate),
		ClearFrequencySec: config.WindowSize,
	}
	if err := t.sampler.Start(); err != nil {
		return fmt.Errorf("error starting dynamic sampler: %v", err)
	}
	return nil
}

func (t *testSampler) send(key string, rate int, done chan struct{}) {
	ticker := time.NewTicker(time.Second / time.Duration(rate))
	defer ticker.Stop()
	for {
		select {
		case <-ticker.C:
			t.sampler.GetSampleRate(key)
		case <-done:
			return
		}
	}
}

func main() {
	cfg := samplerConfig{
		Rate:       50,
		WindowSize: 5,
	}
	t := testSampler{}
	t.init(cfg)
	done := make(chan struct{})

	type testdata struct {
		name        string
		rate        int
		beginAtTick int
		started     bool
	}

	data := []testdata{
		{"200", 100000, 0, false},
		{"301", 1666, 2, false},
		{"403", 1500, 2, false},
		{"401", 315, 2, false},
		{"400", 35, 2, false},
		{"304", 13, 2, false},
		{"201", 7, 2, false},
		{"429", 7, 2, false},
		{"408", 4, 2, false},
		{"204", 4, 2, false},
		{"413", 2, 2, false},
		{"499", 2, 2, false},
		{"404", 1, 2, false},
		{"302", 1, 2, false},
		{"303", 1, 2, false},
		{"415", 1, 2, false},
		{"206", 1, 2, false},
		{"504", 1, 2, false},
		{"502", 1, 2, false},
		{"STOP", 0, 3600, false},
	}

	ticker := time.NewTicker(time.Second)
	currentTick := 0
	var rates map[string]int
outer:
	for {
		select {
		case <-ticker.C:
			currentTick++
			rates = make(map[string]int)
			for i, dt := range data {
				if !dt.started {
					if currentTick > dt.beginAtTick {
						if dt.name == "STOP" {
							ticker.Stop()
							close(done)
							data[i].started = true
							fmt.Println("stopping")
							break
						} else {
							fmt.Println("starting " + dt.name)
							data[i].started = true
							go t.send(dt.name, dt.rate, done)
						}
					}
				} else {
					// do all the ones with a rate higher than 1, the others happen less often.
					if dt.rate > 1 || rand.Intn(10) == 0 {
						rates[dt.name] = t.sampler.GetSampleRate(dt.name)
					}
				}
			}
			fmt.Println(rates)
		case <-done:
			break outer
		}
	}
	fmt.Println(rates)
}